'Built in' Adjustment

[Sterob]

I certainly don't like the idea of built in slop but I guess it has to be done.
I may use your method Kit. Only drill out the holes one has to.....We will see.

[JAZZCNC]

The idea of more adjustability isn't so much about oversized holes but rather not limiting adjustment by machining in groves etc locking plates to other plates.
In an ideal world machining in reference edges etc is how you would do it but this only works if the whole machine is done this way so everything aligns perfectly. In the DIY world, this isn't so easy to do because you really need another machine to do it.
So not limiting adjustment so if you need to tweak alignment etc it can be done by either opening a few holes or thinking about it from the start and putting slots in plates etc.

One of the methods I use in critical areas that need locking is to machine slots into the plates to allow adjustments, then when all setup I lock the plates together using tapered dowel pins.

The key at DIY level is to not restrict adjustment and when designing think about how the adjustment and alignment can be done.